Mapping three decades of air pollution-lung cancer research: trends, hotspots, and networks (1990-2025)

Our plain-English summary of Mapping three decades of air pollution-lung cancer research: trends, hotspots, and networks (1990-2025), by H. Fan, L. Wang, L. Zhai, et al (Frontiers in Oncology, 2025).

The study

• Authors: H. Fan, L. Wang, L. Zhai, S. Deng, Y. Li, H. Niu, B. Zhao, J. Gao, X. Gao
• Journal: Frontiers in Oncology
• Published: 2025;15:1698246
• Type of article: Systematic review
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The relationship between air pollution and lung cancer has attracted considerable attention from researchers worldwide. To systematically assess the scholarly landscape and pinpoint research fronts, this study employs bibliometric analysis to delineate global trends, collaborative networks, and key publications within this field.

Methods: Publications from 1990 to 2025 were extracted from Web of Science Core Collection and Scopus databases. Bibliometric tools including VOSViewer, Citespace, and Bibliometrix R were used to examine trends, key contributors, research themes, and prominent journals.

Results: Among 4,238 publications, citation rates rose significantly. China produced the most publications, with leading institutions such as Harvard University and the Chinese Academy of Sciences. Key researchers included Lan Q, Rothman N, and Vermeulen R. Major journals were Environmental Health Perspectives and Atmospheric Environment. Frequently used keywords like "Lung Cancer" and "Particulate Matter" indicate core themes, while emerging terms such as "Covid-19" and "Machine Learning" reflect evolving interests.

Conclusion: Fine particulate matter is an established environmental risk factor for lung cancer, and research on polycyclic aromatic hydrocarbons and asbestos remains active. The field has shifted from exposure assessment to mechanistic investigations focusing on oxidative stress, gene expression, and machine learning applications, defining key future research directions.

Copyright © 2025 Fan, Wang, Zhai, Deng, Li, Niu, Zhao, Gao and Gao.

In plain English

This article is a bibliometric analysis: it counted and mapped published research rather than studying people or measuring anyone's exposure. The authors searched Web of Science Core Collection and Scopus on July 7, 2025, for English-language articles and reviews from 1990 to 2025 on air pollution and lung cancer. They analyzed 4,238 unique publications (3,960 articles and 278 reviews). Yearly output rose from 35 publications in 1990 to a peak of 380 in 2024. The authors said the lower 2025 count was likely an artifact of indexing delay. China led with 412 articles (9.7%), followed by the United States with 291 (6.9%). The article's supplementary table counts these by the corresponding author's country. In the keyword timeline, "Asbestos" appeared among earlier research topics, and one of 15 keyword clusters was labeled "asbestos exposure." The authors concluded that the field shifted from exposure assessment toward mechanistic research and machine learning. They also wrote that research on polycyclic aromatic hydrocarbons and asbestos remains active. They noted that using only two databases and English-language papers could miss relevant work, and that bibliometric methods do not assess publication quality.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Bibliometric analysis of published literature (labeled by the journal as a systematic review)
• Who was studied: 4,238 unique publications (3,960 articles and 278 reviews) on air pollution and lung cancer, published in English from 1990 to 2025 and retrieved from Web of Science Core Collection and Scopus in a search on July 7, 2025
• Exposure: Air pollution in general, defined by search terms (air pollution, air quality, air pollutants, environmental pollution). No specific fiber type or asbestos exposure was studied; asbestos appeared only as a research topic within the literature.
• Main results:
  • Annual publications rose from 35 in 1990 to 302 in 2025, with a peak of 380 in 2024. The authors considered the lower 2025 figure likely an artifact of database indexing delay.
  • By country, China had 412 articles (9.7%) and the United States 291 (6.9%). The article's supplementary table for country output is based on corresponding-author contributions. Multi-country publications made up 39.5% of United States output and 26.2% of China's output.
  • By institution, Harvard University had 146 publications, Utrecht University 115, and the Chinese Academy of Sciences 106.
  • Science of the Total Environment published the most papers in the set (over 150).
  • Among cited references, Raaschou-Nielsen's 2013 Lancet Oncology paper had the strongest citation burst (strength 16.31, 2014 to 2018).
  • In the keyword timeline, earlier studies focused on topics including "Radon Exposure," "Asbestos," "Nitrogen Dioxide" and "Cancer Incidence." More recent keywords included "Covid-19," "Machine Learning," "Oxidative Stress" and "Gene Expression."
  • Keyword analysis produced 15 thematic clusters, one of which was labeled "asbestos exposure" (Cluster #8) and was linked to the central "lung cancer" cluster.
• The authors' conclusion: The authors concluded that the field has moved from classical exposure assessment toward mechanistic investigations and machine learning applications. They also wrote that research on polycyclic aromatic hydrocarbons and asbestos remains active.
• Limitations the authors state:
  • Using only Web of Science Core Collection and Scopus may have missed studies indexed elsewhere, such as PubMed or CNKI.
  • Restricting the search to English-language articles from 1990 onward could introduce language bias and exclude earlier or non-English works.
  • The analysis is a snapshot up to 2025, and rankings, especially for recent papers, will change as citations accrue.
  • Bibliometric methods are quantitative and do not assess publication quality. Citation counts are also affected by journal visibility and language.

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Oxidative Stress.

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